Okay, so over on Omnimaga, I made a simple "virus" program that would display ones and zeros non-stop unless you very specifically pressed in the correct order:
1) [down]+[left]
2) [enter]+[-]
3) [up]+[down]+[left]+[right]
Since it is an assembly program, you cannot just press on to exit and taking out the batteries will cause a RAM clear.

Well, one day I got a message from Homer-16 requesting a source that was similar so that he could make an unstoppable rick roll… so I made a version that let him display the lyrics in ASCII but I also gave him a few bytes that cleared the screen, jumped to the next line, or put the cursor back to the upper left corner. Anyway, he did the looooong work of putting in the ASCII text, but the program is quite lovely.

The man shuddered as the shadow drew a glistening sword from his back. Creeping closer and closer with his pale eyes burning into the man, the shadow slowly raised his blade and before he could thrust it down, the man heard the shadow hiss something.
"The Shadow Clan's presence must be like a whisper. Always felt, but never seen…"

Haha, I had forgotten that I had posted this here! It is definitely a clever little "virus" if you can get it on a calculator. Or you could use it to prevent people from trying to clear your RAM, while rickrolling them (unless they take out he batteries).

Yep, I have personally tried his rickroll and nyancat videos. There is a reason for why he is known for his ability with grayscale. He even has an option to boot the calculator with an 8-level grayscale image on startup in his zStart app.